While sails have been used for propelling a vehicle over water, land and ice for ages, no device could be found which anticipated the combination of the present invention. Batten sockets, some known as camber inducers, by themselves are old and the mast and batten sockets have been covered by a sleeve in the leading edge of a conventional sail. The most pertinent prior art of which applicant is aware consists of the following U.S. Pat. Nos. 2,077,685; 2,569,318; 3,487,800; 4,064,821; 4,335,669; 4,341,176; 4,386,574; 4,530,301 and foreign patents: French Pat. No. 2,541,230; and British Patent No. GB 2 085 387 A.